Increased disease activity in a patient with sarcoidosis after high dose interleukin 2 treatment for metastatic renal cancer

Sarcoidosis is a disease of unknown aetiology in which cytokines such as interleukin 2 (IL-2) are thought to play an important role. We present the case history of a 48 year old man with sarcoidosis who received treatment with high dose IL-2 for metastatic renal cell cancer, following which he developed hypercalcaemia characterised by a raised level of 1,25-dihydroxyvitamin D (1,25-(OH)₂-D₃), a finding consistent with sarcoidosis associated hypercalcaemia. The increased activity in his sarcoidosis following IL-2 treatment provides direct supportive evidence for the role of IL-2 in the pathogenesis of sarcoidosis.